Fetal weight can be calculated roughly on the basis of fetal biparietal diameter, abdominal circumference and femur length, but it can also be calculated on the basis of the uterine height and abdominal circumference of the pregnant woman. However, there are certain errors in each method of calculation. 1. Fetal Biparietal Diameter: Fetal weight (g) = Biparietal Diameter (cm) x 900-5200. 2. Fetal abdominal circumference: Fetal weight (g)=-2686.60+171.48×abdominal circumference. 3. Fetal femur length: fetal weight (g)=-2232.56+747.42×femur length. 4. Maternal uterine height-abdominal circumference: fetal weight (g) = uterine height × abdominal circumference + 200. The assessment of fetal weight does not represent the actual weight of the baby after birth and there is a certain degree of error. It is recommended to judge the fetal weight scientifically under the guidance of professional doctors.